The present invention relates to a catalyst and process for producing polyurethanes from organic isocyanates and organic polyols.
Polyurethanes typically are produced by the reaction of organic isocyanates with polyester or polyether polyols.
A catalyst useful for producing a polyurethane from an organic polyisocyanate and an organic polyester polyol is disclosed by U.S. Pat. No. 4,326,042 to Zimmerman. This catalyst comprises catalytic amounts of N-methoxypropylmorpholine, N-butylmorpholine, and N,N'-dimethylpiperazine.
U.S. Pat. No. 4,228,248, to Zimmerman, discloses a method for producing a polyurethane by reacting an organic polyisocyanate with an organic polyester or polyether polyol in the presence of an amine which is a N-ethylalkoxy morpholine compound.
Other catalysts useful for producing polyurethanes are known in the art. These catalysts include triethylene diamine, N-ethyl morpholine (NEM), dimethyl amino ethanol, N,N,N',N'-tetramethylethylene diamine and N,N-dimethylbenzylamine (DMBA).
Many of these catalysts, however, suffer from the disadvantage of being toxic to humans. This toxicity increases the hazard of producing polyurethanes, and is of a major concern to polyurethane producers. Many of these catalysts also have the disadvantage of giving off extremely unpleasant odors. These odors make polyurethane producing processes extremely unpleasant to be around, and may result in a product having a residual odor which makes the product unacceptable for its intended use. Although non toxic or non odoriferous catalysts are known in the art, in many instances these catalysts fail to yield polyurethanes with appropriate properties.
This problem is particularly acute with polyurethane foams which require the catalyst to predominantly promote the "gas" reaction, rather than the gelling reaction, in order to produce a foam of appropriate height and foam openness. In addition, the catalyst must cause the reaction to proceed quickly enough to allow a foam of suitable height to form and gel before blowing gases escape.
It is therefore an object of the present invention to provide a catalyst and a process for producing polyurethane foams wherein the catalyst has diminished toxicity and may be used to produce a polyurethane which is substantially odor free.
It is also an object of the present invention to provide a catalyst and process which may be used to produce a polyurethane foam of suitable foam height and foam openness.